Animal-microbe co-evolution and symbiosis are broadly distributed across the animal kingdom. Insects
form a myriad of associations with microbes ranging from vectoring of pathogens to intracellular,
mutualistic relationships. Lower termites are key models for insect-microbe symbiosis because of the
diversity, complexity and functionality of their unique tripartite symbiosis. This collaboration allows
termites to live on a diet of nitrogen-poor lignocellulose. Recent functional investigations of lignocellulose
digestion in lower termites have primarily focused on the contributions of the eukaryotic members
of the termite holobiont (termite and protist). Here, using multiple antimicrobial treatments, we
induced differing degrees of dysbiosis in the termite gut, leading to variably altered symbiont abundance
and diversity, and lignocellulolytic capacity. Although protists are clearly affected by antimicrobial
treatments, our findings provide novel evidence that the removal of distinct groups of bacteria partially
reduces, but does not abolish, the saccharolytic potential of the termite gut holobiont. This is specifically
manifested by reductions of 23e47% and 30e52% in glucose and xylose yields respectively from complex
lignocellulose. Thus, all members of the lower termite holobiont (termite, protist and prokaryotes) are
involved in the process of efficient, sustained lignocellulase activity. This unprecedented quantification of
the relative importance of prokaryotes in this system emphasizes the collaborative nature of the termite
holobiont, and the relevance of lower termites as models for inter-domain symbioses.